The present invention relates generally to a sole structure for a baseball spiked shoe, and more particularly, to improvement in structure of said sole structure.
Japanese patent application publication No. 1996-84605 discloses a sole for a sports shoe in which a through hole with an annular engagement portion is formed at a heel portion of the sole and a cushioning member of a diameter greater than an inner diameter of the through hole is detachably inserted into the through hole (see paras. [0021]-[0025], [0029] and FIG. 9).
According the description of the above publication, since the cushioning member is translatable upwardly and downwardly inside the through hole, when a sole body receives a ground impact force at time of impact onto the ground the cushioning member expands and contracts vertically independently of the sole body to absorb the impact thereby increasing a ground impact effect of the heel portion (see para. [0031]).
However, in the structure described in the above publication, it tries to absorb the ground impact force by expansion and contraction in a vertical direction of the cushioning member. Owing to that, in order to prevent the cushioning member from falling out of the through hole at the time of expansion and contraction of the cushioning member and also to prevent an upper end of the cushioning member from protruding from the through hole, a plurality of annular engagement portions are required to be formed in the through hole and a plurality of longitudinal grooves that engage with these annular engagement portions are required to be formed in the cushioning member, which makes the structure complicated. Moreover, a gel-like substance as the cushioning member should be provided under a solid member with a longitudinal groove thus making the structure more complicated.
The present invention has been made in view of these circumstances and its object is to provide a simplified sole structure for a baseball spiked shoe that can improve cushioning properties of a heel region of the structure and that can enhance comfortableness in wearing the shoe.
Other objects and advantages of the present invention will be obvious and appear hereinafter.